Zooplankton as Indicators to Detect and Track the Degree of Acid-Stress to Lake Ecosystems

• Main Author: Anas, Mohamed Usoof Mohamed
• Other Authors: Wessel, Bjoern, Leavitt, Peter, Scott, Ken, Donald, David B.
• Format: Thesis
• Language: English
• Published: Faculty of Graduate Studies and Research, University of Regina 2012
• Subjects: Lake acidification > Saskatchewan; Freshwater zooplankton > Effect of water acidification on > Saskatchewan; Lake ecology > Saskatchewan; Athabasca Tar Sands (Alta.) > Environmental aspects > Saskatchewan; Oil sands > Environmental aspects > Saskatchewan; Alta; Fort McMurray
• Online Access: http://hdl.handle.net/10294/3562; http://ourspace.uregina.ca/bitstream/handle/10294/3562/Anas_Mohamed_Usoof_Mohamed_MSC_BIOL_Fall2012.pdf

A Thesis Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements for the Degree of Master of Science in Biology, University of Regina. xiii, 70 l. It is critical to identify and use appropriate ecological indicators to detect, monitor and assess the impacts of environmental stressors on natural systems in order to effectively legislate, protect and restore ecosystems. Based on strong and predictable community responses to acid-stress, crustacean zooplankton has the potential to be a crucial indicator of acidification in freshwater ecosystems. This thesis is based on evaluating the potential of zooplankton as indicators to detect and track the degree of impact of recent acid deposition on Canadian Shield lakes in north-west parts Saskatchewan. These systems may now be at risk as the area is downwind of growing oil-sand operations near Fort McMurray, Alberta, a significant emission source of acidifying agents. Yet, to this point chemical data from past and recent studies of these lakes have not led to any consensus in respect to the degree of impact. In contrast to chemical inferences, concurrent sampling of crustacean zooplankton communities in these lakes indicated strong symptoms of acid-stress, including: 1) distinction of lakes based on species assemblages with different acid tolerances, 2) species-environment relationships strongly related to acid sensitivity, 2) unusually low species richness, 4) low frequency of occurrence of acid-sensitive taxa/species, and 5) opposite trends in changes of relative abundances of acid-sensitive and acid-tolerant taxa/species along the acid-sensitivity gradient. I propose that these responses resulted from seasonal or short-term pH alterations (rather than chronic acidification), which can be critical during early stages of acidification, This emphasizes the importance of biological indicators to assess acid-stress, because biological responses can occur prior to long-term chemical responses are detectable. Subsequently, I ...